Investigating Intentional Clone Refactoring

Software clone refactoring has been studied from many perspectives, including empirical research on clone refactoring history, IDE support for tracking clone change, and recommendation systems for clone management. Most of the work relies on having access to and being able to analyze the history of clone refactoring. However, refactoring cloned code is not equivalent to clone management, as code refactoring can be motivated by goals unrelated to cloning. In this position paper, we introduce a dataset of intentional clone refactoring, which is produced by keywords matching in commit messages within the version control system of Linux kernel. By investigating two important clone evolution scenarios — clone removal and inconsistent changes — in subsystems of Linux kernel, we find that intentional clone refactoring accounts for only a small proportion of all detected clone evolution.